1. Field of the Invention
The present invention relates to electrical cable guides, and more particularly to cable guides for protecting and aligning the anode cable of a tubular sacrificial anode.
2. Prior Art
Tubular sacrificial impressed current anodes have recently been developed for use in cathodic protection systems in severe environments such as deep ground beds or sea water service. These tubular anodes are particularly suited for such use because they substantially reduce localized rapid consumption of the anode.
Such an anode is disclosed in U.S. Pat. No. 4,096,051, assigned to the assignee of the present invention. A hollow tubular anode body has an internally mounted anode cable connection which is isolated from the electrolyte solution by a mastic encapsulated by two circular caps. The cable is insulated and extends through an opening in a cap along the central axis of the anode body to a power source located externally of the anode. The anode cable is centrally positioned within the anode body by an epoxy disc mounted in an end of the anode body which has a centrally located hole through which passes the anode cable.
The purpose for the plastic disc is to center the anode cable and prevent it from rubbing against the interior walls of the anode body during use thereby wearing away the insulation of the anode cable and causing a high rate of rapid consumption of the exposed conductor.
A disadvantage of using such a plastic disc as a cable guide is that, as the anode body oxidizes and shortens in length, the plastic disc is no longer constrained by the walls of the anode body and the anode cable is thereby free to rub against the rough shortened end of the anode body. Therefore, a need exists for a device which will keep the anode cable in the center of the anode body and eliminate abrasive friction during all periods of use.
It has also been found that the disc-shaped cable guide of the prior art may be unsuitable in certain instances for use in harsh environments such as ground beds and deep sea locations. The intense hydrostatic pressures of these environments force small amounts of electrolyte past the seam between the epoxy disc and the anode body and into the interior portion of the anode body where it reacts with the anode body to form corrosive gas which attacks the insulation of the anode cable. Therefore, a need also exists for a cable guide that allows escape of gas formed within the anode body and protects the anode cable from a corrosive environment.